As a device to cool a heating component such as a Central Processing Unit (CPU) mounted on an electronic device, a heat pipe is known. The heat pipe is a device that transports heat using phase change of working fluid.
As an example of a heat pipe, a loop heat pipe may be raised which includes an evaporator that vaporizes working fluid by heat of a heating component and a condenser that condenses the vaporized working fluid. In the loop heat pipe, the evaporator and the condenser are connected by a liquid line and a vapor line that form a loop flow path. In the loop heat pipe, the working fluid flows in the loop flow path in one direction.
Further, a porous body is provided in the liquid line of the loop heat pipe so that the working fluid in the liquid line is induced to the evaporator by capillary force generated in the porous body and vapor is prevented from reversely flowing from the evaporator to the liquid line. A plurality of pores are formed in the porous body. Each of the pores is formed by stacking a plurality of metal layers in each of which through holes are formed such that the through holes of different metal layers partially overlap (see Patent Document 1, for example).
However, it is difficult to stack the metal layers, in each of which the through holes are formed, such that the through holes of different metal layers partially overlap for all of the pores, for the following reasons. First, a positional shift of the metal layers may occur when stacking the plurality of metal layers. Second, a positional shift may occur due to expansion and contraction of the metal layers when heating the metal layers while stacking the metal layers. Third, positional shifts of the through holes occur when forming the through holes in each of the metal layers.
If such positional shifts occur, pores each having a predetermined size cannot be formed, and capillary force generated by the pores is lowered. Thus, an effect of suppressing a backflow of vapor from an evaporator to a liquid line cannot be sufficiently obtained.
[Patent Document]
[Patent Document 1] WO 2015/087451